package com.zenchn.utils;


import com.zenchn.entity.LatLon;

/**
 * 各地图API坐标系统比较与转换; 
 * WGS84坐标系：即地球坐标系，国际上通用的坐标系。设备一般包含LatLon芯片或者北斗芯片获取的经纬度为WGS84地理坐标系, 
 * 谷歌地图采用的是WGS84地理坐标系（中国范围除外）; 
 * GCJ02坐标系：即火星坐标系，是由中国国家测绘局制订的地理信息系统的坐标系统。由WGS84坐标系经加密后的坐标系。 
 * 谷歌中国地图和搜搜中国地图采用的是GCJ02地理坐标系; BD09坐标系：即百度坐标系，GCJ02坐标系经加密后的坐标系; 
 * 搜狗坐标系、图吧坐标系等，估计也是在GCJ02基础上加密而成的。
 *
 * @author   dinxinfa
 */  
public class PositionUtil {  
      
    public static final String BAIDU_LBS_TYPE = "bd09ll";  
      
    public static double pi = Math.PI; 
    public static double a = 6378245.0;  
    public static double ee = 0.00669342162296594323;  
  
    /** 
     * 84 to 火星坐标系 (GCJ-02) World Geodetic System ==> Mars Geodetic System 
     *  
     * @param lat 
     * @param lon 
     * @return 
     */  
    public static LatLon latLon84ToGcj02(double lat, double lon) {
        if (outOfChina(lat, lon)) {  
            return null;  
        }  
        double dLat = transformLat(lon - 105.0, lat - 35.0);  
        double dLon = transformLon(lon - 105.0, lat - 35.0);  
        double radLat = lat / 180.0 * pi;  
        double magic = Math.sin(radLat);  
        magic = 1 - ee * magic * magic;  
        double sqrtMagic = Math.sqrt(magic);  
        dLat = (dLat * 180.0) / ((a * (1 - ee)) / (magic * sqrtMagic) * pi);  
        dLon = (dLon * 180.0) / (a / sqrtMagic * Math.cos(radLat) * pi);  
        double mgLat = lat + dLat;  
        double mgLon = lon + dLon;  
        return new LatLon(mgLat, mgLon);  
    }  
  
    /** 
     * * 火星坐标系 (GCJ-02) to 84 * * @param lon * @param lat * @return 
     * */  
    public static LatLon gcjToLatLon84(double lat, double lon) {
        LatLon latLon = transform(lat, lon);
        double lontitude = lon * 2 - latLon.getLon();
        double latitude = lat * 2 - latLon.getLat();
        return new LatLon(latitude, lontitude);  
    }  
  
    /** 
     * 火星坐标系 (GCJ-02) 与百度坐标系 (BD-09) 的转换算法 将 GCJ-02 坐标转换成 BD-09 坐标 
     *  
     * @param ggLat
     * @param ggLon
     */  
    public static LatLon gcj02ToBd09(double ggLat, double ggLon) {
        double x = ggLon, y = ggLat;
        double z = Math.sqrt(x * x + y * y) + 0.00002 * Math.sin(y * pi);  
        double theta = Math.atan2(y, x) + 0.000003 * Math.cos(x * pi);  
        double bdLon = z * Math.cos(theta) + 0.0065;
        double bdLat = z * Math.sin(theta) + 0.006;
        return new LatLon(bdLat, bdLon);
    }  
  
    /** 
     * * 火星坐标系 (GCJ-02) 与百度坐标系 (BD-09) 的转换算法 * * 将 BD-09 坐标转换成GCJ-02 坐标 * * @param 
     * bd_lat * @param bd_lon * @return 
     */  
    public static LatLon bd09ToGcj02(double bdLat, double bdLon) {
        double x = bdLon - 0.0065, y = bdLat - 0.006;
        double z = Math.sqrt(x * x + y * y) - 0.00002 * Math.sin(y * pi);  
        double theta = Math.atan2(y, x) - 0.000003 * Math.cos(x * pi);  
        double ggLon = z * Math.cos(theta);
        double ggLat = z * Math.sin(theta);
        return new LatLon(ggLat, ggLon);
    }  
  
    /** 
     * (BD-09)-->84 
     * @param bdLat
     * @param bdLon
     * @return 
     */  
    public static LatLon bd09ToLatLon84(double bdLat, double bdLon) {
  
        LatLon gcj02 = PositionUtil.bd09ToGcj02(bdLat, bdLon);
        LatLon map84 = PositionUtil.gcjToLatLon84(gcj02.getLat(),
                gcj02.getLon());  
        return map84;  
  
    }  
  
    public static boolean outOfChina(double lat, double lon) {
        double minLon=72.004;
        double maxLon=137.8347;
        double minLat=0.8293;
        double maxLat=55.8271;

        if (lon < minLon || lon > maxLon) {
            return true;
        }
        if (lat < minLat || lat > maxLat)  {
            return true;
        }
        return false;
    }  
  
    public static LatLon transform(double lat, double lon) {  
        if (outOfChina(lat, lon)) {  
            return new LatLon(lat, lon);  
        }  
        double dLat = transformLat(lon - 105.0, lat - 35.0);  
        double dLon = transformLon(lon - 105.0, lat - 35.0);  
        double radLat = lat / 180.0 * pi;  
        double magic = Math.sin(radLat);  
        magic = 1 - ee * magic * magic;  
        double sqrtMagic = Math.sqrt(magic);  
        dLat = (dLat * 180.0) / ((a * (1 - ee)) / (magic * sqrtMagic) * pi);  
        dLon = (dLon * 180.0) / (a / sqrtMagic * Math.cos(radLat) * pi);  
        double mgLat = lat + dLat;  
        double mgLon = lon + dLon;  
        return new LatLon(mgLat, mgLon);  
    }  
  
    public static double transformLat(double x, double y) {  
        double ret = -100.0 + 2.0 * x + 3.0 * y + 0.2 * y * y + 0.1 * x * y  
                + 0.2 * Math.sqrt(Math.abs(x));  
        ret += (20.0 * Math.sin(6.0 * x * pi) + 20.0 * Math.sin(2.0 * x * pi)) * 2.0 / 3.0;  
        ret += (20.0 * Math.sin(y * pi) + 40.0 * Math.sin(y / 3.0 * pi)) * 2.0 / 3.0;  
        ret += (160.0 * Math.sin(y / 12.0 * pi) + 320 * Math.sin(y * pi / 30.0)) * 2.0 / 3.0;  
        return ret;  
    }  
  
    public static double transformLon(double x, double y) {  
        double ret = 300.0 + x + 2.0 * y + 0.1 * x * x + 0.1 * x * y + 0.1  
                * Math.sqrt(Math.abs(x));  
        ret += (20.0 * Math.sin(6.0 * x * pi) + 20.0 * Math.sin(2.0 * x * pi)) * 2.0 / 3.0;  
        ret += (20.0 * Math.sin(x * pi) + 40.0 * Math.sin(x / 3.0 * pi)) * 2.0 / 3.0;  
        ret += (150.0 * Math.sin(x / 12.0 * pi) + 300.0 * Math.sin(x / 30.0  
                * pi)) * 2.0 / 3.0;  
        return ret;  
    }  

}  